1. Technical Field
The subject invention relates to deburring tools and is particularly concerned with the construction of a deburring tool having a replaceable and adjustable cutting head.
2. Description Of The Prior Art
Deburring tools are generally employed to deburr passages bored through workpieces such as valve bodies and the like and to put a chamfer on the edges of the hole in the workpiece at the opening of the passages. Examples of deburring tools known in the prior art are disclosed by the present inventor, William R. Robinson along with James L. Roberts in U.S. Pat. No. 4,086,018 issued Apr. 25, 1978 and by William R. Robinson in U.S. Pat. No. 4,147,463 issued Apr. 3, 1979 for an adjustable deburring tool.
Deburring tools of this type generally include an elongated cylindrical arbor formed with a cutting blade recess. A unitary cutting tool is received in the recess and includes a cutting head with an integral, elongated, flat, resilient blade extending therefrom. The blade is mounted in the arbor by a pair of axially spaced pins, at least one of which, the roll pin, extends through a hole in the blade to define a pivot point about which the blade can flex.
The other pin engages the end of the blade opposite the cutting head and holds this end in non-pivotal relationship with respect to the arbor with the cutting head projecting from the recess for engaging the workpiece. The cutting head is thereby resiliently yieldable to permit the cutting head to move inwardly with respect to the recess during a deburring operation.
While deburring tools of the prior art generally perform satisfactorily, they are not without their problems. For example, in order to replace a worn out cutting tool, an operator must remove the deburring tool from the machine, drive the roll pin completely through the hole in the blade and out of the arbor, remove the old blade from the arbor, replace it with a new blade and then drive the roll pin back into the arbor and through the hole in the new blade. In addition to this complication, the roll pin has a limited useful life of approximately one to three blade changes.
Cutting blades used in the prior art are generally stamped from steel stock and a hole then drilled to accept the roll pin. The blade is then heat treated to increase its hardness. Recently, it has been found that cutting blades may be cut from hardened M-2 high speed tool steel stock using a wire electrical discharge machine. This improvement is disclosed by James R. Robinson in U.S. Ser. No. 925,957, now U.S. Pat. No. 5,277,528, directed toward a Micro Deburring Tool. However, problems have been encountered in the process of drilling the hole in the blade to accept the roll pin. In these cases, the drill is no harder than the blade and therefore will not bore the hole.